Single correct option
A boat covers 30 km downstream in 2 hours and the same 30 km upstream in 3 hours. What is the speed of the boat in still water?
- A. 10 km/h
- B. 11 km/h
- C. 12.5 km/h
- D. 15 km/h
Show answer and solution
Answer: (C) 12.5 km/h
Downstream speed = 30/2 = 15 km/h, Upstream speed = 30/3 = 10 km/h. Speed in still water = (downstream + upstream)/2 = (15+10)/2 = 12.5 km/h. (Speed of current = (15−10)/2 = 2.5 km/h, though not asked here.)
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